The Safe Use of Essential Oils with Medications: Part II

As essential oils become an increasingly popular wellness tool, it’s important to consider how incorporating them into mainstream medicine can be done safely. For most, it is comforting to know, that when used as intended and with common sense, the documented safety of essential oils is impressive.

However, the combining of essential oils with medications has not been extensively studied. Further complicating this matter is the divergent views and trainings amongst aromatherapists.1As mentioned in my previous article, my suggestions are based on my research and 13+ years of experience of using essential oils personally and with my clients. The essential oils I use are standardized oils of high quality that combine the applications of inhalation, topical, and ingestion. They are not diluted or cut, alerted, or altered in any way.2 I cannot speak for those who wish to use essential oils that aren’t of highest quality.

In Part I, I reviewed four general guidelines to consider when using essential oils with medications. These included:

Adjusting dosages of either as needed.

Spacing out time between medication and essential oil use. I also reviewed why to be cautious when on blood thinners in relationship to timing and dosage.

Why not to drink grapefruit juice or use grapefruit oil when on certain medications. This is because this pink fruit inhibits an enzyme needed to process various drugs.

Caution Down Peppermint Lane

Peppermint has exhibited in vitro and vivo modulation of the motility of the digestive tract. Therefore, any medications that affect digestion could potentially interact with peppermint oil. It’s also important to note that any drugs that decrease stomach pH, such as H2 blockers or proton pump inhibitors (“antacids”), could theoretically cause enteric coated capsules of peppermint to dissolve earlier. This could lead to irritation in the stomach. (Enteric coating is used to prevent absorption in the stomach).

Natural Standard Database also reports potential interactions of peppermint with drugs that are metabolized by a certain liver enzyme, P4503A4.3However, this is more theoretical evidence and has not been demonstrated to be true in humans.3-4

The potential interaction of peppermint with nifedipine (a blood pressure medication) was also studied in vitro using human liver cells. Peppermint oil and its constituents menthol, menthyl acetate moderately, reversibly inhibited a metabolizing enzyme, which caused an increase amount in the body of this calcium channel blocker. The researchers noted, “this requires further investigation.”5

Essential Oils Use With Antibiotics- Is It OK or NAY?

There is in vitro evidence that that using essential oils with antibiotics have synergistic effects.6-`5One study investigated the relationship between several essential oils and beta-lactam antibiotics for their antibacterial effect against multidrug resistant bacteria. The authors concluded, “The finding highlighted the potential of peppermint, cinnamon bark and lavender essential oils being as antibiotic resistance modifying agent. Reduced usage of antibiotics could be employed as a treatment strategy to decrease the adverse effects and possibly to reverse the beta-lactam antibiotic resistance.” 6

In another in vitro study, a combination of essential oils with various antibiotics was tested in order to determine if their combined actions would be useful against antibacterial resistance. The authors found that 4 out of the 35 essential oil-antibiotic pairs showed synergistic effects and there was no interaction between the other pairs.7

Finally, another study demonstrated that an active constituent in oregano, carvacrol, exhibited inhibition of biofilms against microbes. Microbes form biofilms as a means to evade immune detection and are a known mechanism of resistance with superbugs.16

Unfortunately, human trials are lacking in combining both essential oils and antibiotics together, though the promise of this synergism with less resistance seems intriguing. This means, essential oils may actually assist with less resistance. This is something to consider with your doctor.

If you wish to ere on the side of caution, it may be best to stick with diffusing and topical applications rather than oral use, if one is taking an antibiotic medication. Furthermore, if you are going to take any form of microbe inhibitors, natural or synthetic, consider supplementing with a probiotic. I like S. boualardii, because of its diverse actions and clinical studies that support its use with antibiotics. 17-19

In a rodent study, the essential oil (EO) of caraway, prepared as emulsion, was applied to male mice for 5 consecutive days. 200mg/kg of Paracetamol was then applied orally or in an injection 2 hours after the last EO dose. The authors found different effects in medication levels based on route of administration. With oral dosage, there was less paracetamol in the rodent’s body. After injection, there was enhanced body exposure to the drug with the EO.

This study demonstrates the importance of spacing or avoiding caraway if taking acetaminophen. However, it has not been found in humans. 20

Avoid Anise with CNS Drugs

A potential interaction was demonstrated between codeine, diazepam, midazolam, pentobarbital, imipramine and fluoxetine in mice after 5days of pretreatment of aniseed EO. The authors found various modulatory effects between medications and anise EO. 21

General Precautions

The following precautions are based on theoretical and mechanisms of action of various essential oils.22-23

Sarah Lobisco, ND, is a graduate of the University of Bridgeport’s College of Naturopathic Medicine (UBCNM). She is licensed in Vermont as a naturopathic doctor and holds a Bachelor of Psychology from State University of New York at Geneseo. Dr. LoBisco is a speaker on integrative health, has several publications, and is a certification candidate in functional medicine. Currently, she is the Director of Clinical Education for an esteemed nutraceutical company.

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